find_in_set.cc

/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
 *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
 *
 *  Copyright (C) 2008 Sun Microsystems, Inc.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; version 2 of the License.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include <config.h>

#include <drizzled/charset.h>
#include <drizzled/function/find_in_set.h>

/* Search after a string in a string of strings separated by ',' */
/* Returns number of found type >= 1 or 0 if not found */
/* This optimizes searching in enums to bit testing! */

namespace drizzled
{

void Item_func_find_in_set::fix_length_and_dec()
{
  decimals=0;
  max_length=3;                                 // 1-999
  agg_arg_charsets(cmp_collation, args, 2, MY_COLL_CMP_CONV, 1);
}

static const char separator=',';

int64_t Item_func_find_in_set::val_int()
{
  assert(fixed == 1);
  if (enum_value)
  {
    uint64_t tmp=(uint64_t) args[1]->val_int();
    if (!(null_value=args[1]->null_value || args[0]->null_value))
    {
      if (tmp & enum_bit)
  return enum_value;
    }
    return 0L;
  }

  String *find=args[0]->val_str(&value);
  String *buffer=args[1]->val_str(&value2);
  if (!find || !buffer)
  {
    null_value=1;
    return 0;
  }
  null_value=0;

  if (buffer->length() >= find->length())  
  {
    my_wc_t wc;
    const charset_info_st * const cs= cmp_collation.collation;
    const char *str_begin= buffer->ptr();
    const char *str_end= buffer->ptr();
    const char *real_end= str_end+buffer->length();
    const unsigned char *find_str= (const unsigned char *) find->ptr();
    uint32_t find_str_len= find->length();
    int position= 0;
    while (1)
    {
      int symbol_len;
      if ((symbol_len= cs->cset->mb_wc(cs, &wc, (unsigned char*) str_end, (unsigned char*) real_end)) > 0)
      {
        const char *substr_end= str_end + symbol_len;
        bool is_last_item= (substr_end == real_end);
        bool is_separator= (wc == (my_wc_t) separator);
        if (is_separator || is_last_item)
        {
          position++;
          if (is_last_item && !is_separator)
            str_end= substr_end;
          if (!my_strnncoll(cs, (const unsigned char *) str_begin,
                            str_end - str_begin,
                            find_str, find_str_len))
            return (int64_t) position;
          else
            str_begin= substr_end;
        }
        str_end= substr_end;
      }
      else if (str_end - str_begin == 0 &&
               find_str_len == 0 &&
               wc == (my_wc_t) separator)
        return (int64_t) ++position;
      else
        return 0;
    }
  }
  return 0;
}

} /* namespace drizzled */